CUSHIONING STRUCTURE OF AUTOMOBILE SEAT

Abstract: A cushioning structure equipped with flat bonding material for simplifying fitting of a cushioning material to a surface material for forming an automobile seat. A flat bonding member (12) consisting of a flat bonding material (13) bonded to a support material (14) having fundamentally the same material as a cushioning material (11) is fitted inside a cushioning material shaping mold (20), and a cushion body is formed by integrating the flat bonding member (12) with the cushioning material along a three-dimensional curved shape of the inner surface of the mold by the internal pressure due to expansion molding of the cushioning material.

Description: The present invention relates to a cushion body for a car seat and, in particular, relates to a cushion body of a car seat to which a surface material is attached through a fastener member fixed conformably on a three-dimensional curved surface of a cushioning material forming the cushion body. Several methods for fixing a surface material on a surface of a cushioning material which is made of a foamed body and is a main part of an automobile seat have been known and used in public. In the prior art, in order to fix a surface material on a cushioning material having a concave surface shape about the center thereof, a back side surface of the surface material was bonded on a surface of the cushioning material, or a surface material was fixed on a cushioning material by injecting urethane in a mold after setting the surface material therein. However, in such methods for fixing or bonding a surface material on a cushioning material, their own production systems are required, and it is difficult to install such systems in a continuous assembly line. Thus, the cost for installing the system is increased. Also, because automobile seats are made by mass production, it is required to maintain high productivity because a lower volume results in a rise in cost. In order to avoid such disadvantages, a flat fastening material is used for attaching a surface material on a cushioning material. This flat fastening material is called a flat fastener or flat fastener material. The fastener is made of tufting many hooked or ring-shaped small protrusions on a base sheet of the fastener. The hooked or ring-shaped small protrusions can hook and mechanically attach to a fabric which forms the back side of the surface material. It is found that since the surface material can be easily separated away from the fastener, while the surface material cannot be moved in a direction parallel to the fastener, such a fastener material as means for attaching a surface material on a cushion body is relatively superior. An example of an arrangement of the type mentioned above is disclosed in FR-A-2423666. Since the flat fastener material is basically a two-dimensional planar shape, if a seating part of a seat has a relatively flat planar shape, such a flat fastener material can be adhered to a flat surface of the seating part, and a surface material can be attached the seat through the flat fastener material by pressurizing the flat fastener material thereon. However, if a seating part of a seat has a three-dimensional curved shape, it is difficult to conformably adhere such a flat fastener material to a three-dimensional curved surface of a cushioning material. Therefore, an object of the present invention is to provide a cushion body of a car seat in which a flat fastener material is fixed conformably to a seating part of the seat having a three-dimensional curved surface shape. A car seat cushion comprising a cushioning material having a seating surface, a fastener body having an undersurface affixed to said seating surface and an upper surface having a plurality of fasteners disposed thereon, and a surface material covering said cushioning material and attached to said fasteners, characterised in that the cushioning material is formed by injection moulding to have a center portion and rising side portions to either side of said center portion, said center portion having a three-dimensional curved surface, and said fastener body is inserted as a planar body in the portion of the mould corresponding to the center portion and moulded with the cushion material whereby the injection moulding pressure causes the fastener body to have an upper surface duplicating the three-dimensional curved surface of said center portion whereby the surface material assumes the three-dimensional curved shape of the seating surface. The preferred cushion according to the invention is made by fixing the fastener body on the cushioning material by positioning the flat fastener body in a mold for shaping the cushioning material along a three-dimensional curved shape of the mold and then injecting a liquefied foamable composition in the mold to form and shape the cushioning material in the mold. The fastener body is basically the same material as the cushioning material. The fastener body preferably comprises a fastener material and a supporting material. To fix the fastener material on the supporting material layer, an adhesive may be used. Alternatively, it may be done by setting the fastener material in a mold and pouring and molding a foamable composition forming the supporting material layer or slab in the mold so that the fastener becomes integral with the supporting material. An example of such an "expansion molding" process is shown in FR-A-2115433. When the cushioning material is made of urethane, it is preferable to use a urethane material (a slab) as the supporting material layer and to fix the fastener material on the slab by lamination. The thickness of the slab which is not specially limited, is 5-15mm and preferably 10mm. Such a fastener body is attached on at least a central main part of a seating portion of the cushioning material so that the cushion body is formed. Upon placing a surface material on the fastener body and strongly pressuring it, a fabric of a back surface of the surface material is securely hooked on the fastener material so that the surface material is attached on the cushion body, and thus a car seat may be easily and speedily produced. According to the present invention, by pre-producing a certain number of such a cushion body with the fastener body, it is possible to rapidly and competently respond to various orders by covering and attaching surface materials on the cushion bodies in accordance with the amount of orders received, and it is unnecessary to provide large scaled and ineffective production systems such as conventional surface integral molding, and it becomes easy to contribute to reducing the cost of the product. Brief description of the drawings Figure 1 is a perspective view depicting a car seat having a seating surface having a three-dimensional curved surface shape pursuant the present invention, and a fixation position of a fastener body according to the present invention is shown as an example by dotted lines. Figure 2 is a cross sectional view of a cushion body taken along a line A -A of the seat shown in Figure 1 with only a left hand side of a surface material attaching to a fastener material being shown by a dotted line. Figure 3 is a sectional view of a mold forming a cushion body with a fastener body consisting of a fastener material and a supporting material shown in Figure 2, and the fastener body attached to a surface of the mold is shown in a condition before injecting a foamable composition therein (by a dotted line) and is shown in a condition after foaming it (by a solid line). Referring to the drawings, a preferred embodiment of the present invention is described in the following description. Figure 1 is a perspective view describing one example of a car seat. The seating surface of the seat is a three-dimensional curved surface depicted by three lines, A-A, B-B and C-C, to express the geometry of the curved surface. As seen by lines A-A and C-C, a front part of a central portion of the seating surface arises at the center (an intersection of A and C indicated by number 1) and lowered from the center to left and right hand sides, and a bucket--shaped seat is formed by sharply rising up at the left and right hand sides, as seen by numbers 2 and 3. In contrast, as seen by line B-B, the rear part of the center is depressed at the intersection 4, and the seating surface is slightly rising up to the left and right hand sides and is then continuously rising up to the side portions 5 and 6. Both heights of the side portions 5 and 6 are smaller than the side portions 2 and 3. While a seat having such a three-dimensional curved surface formed thereon can be fitted with a figure of a person who sits on the seat, there has not existed a seat made by attaching a fastener material over such a three-dimensional curved surface before the present invention. The fastener body 12 of the present invention is generally attached over the whole width of the center portion on a seat surface having such a three-dimensional curved surface. The fastener body 12 forms the three-dimensional curved surface together with a cushioning material (indicated by number 11 in Figure 2), and the fastener body 12 and the side portions of the cushioning material 11 are covered with a surface material (indicated by number 15 in Figure 2). This cushion body 10 basically consists of a cushioning material 11 and fastener body 12. The fastener body 12 must have a predetermined three-dimensional curved surface and is connected with the cushioning material 11. In a preferred embodiment, the fastener body 12 to be attached to the cushioning material 11 is made by connecting the fastener material 13 (preferably, a hook or protrusion type surface fastener commercially sold by a company named KURARE Inc.) with a slab-urethane layer as a supporting material layer. Note that the fastener body 12 and the fastener material 13 are basically flat. While the fastener material 13 and the slab-urethane layer 14 may be bonded by an adhesive, it is preferably to fuse and laminate the fastener material 13 on the slab-urethane layer 14. The under surface of the slab-urethane layer 14 is connected with a cushioning material 11 made of a urethane foam, and such a connection is done by injecting and foaming urethane composition in a mold and foaming the composition therein. The cushion body 10 is made by connecting the cushioning material 11 with the fastener body 12. The seat is completed by attaching a suitable surface material 15 thereon. While the surface material 15 indicated by a dotted line covers only the left hand side of the seat in Figure 2, the surface material 15 is also readily attached on the fastener material 13 and the cushioning material 11 on the right hand side, symmetrical to the left hand side. The back surface of the surface material 15 is fastened with the small protrusions (not shown in the drawing figures because they are so small) provided on the fastener material 13, and a good fastening force is exhibited thereby. In addition, a sutured part of the surface material 15 is shown as indicated by number 16 in Figure 2. While the sutured part thereof is shown as accommodated in a gap 17 between the cushioning material 11 and the fastener body 12, it is not necessarily so limited in this configuration. Such a cushion body 10 of the present invention is manufactured by using a mold as shown in Figure 3. In a lower portion 20 of the mold, the center portion thereof is a bottom surface 21 having a predetermined three-dimensional curved surface. A geometry formed by the lower portion 20 and an upper portion 24 of the mold shown in Figure 3 is generally corresponding to a section cut along line A-A of Figure 1 and the cross-sectional view depicted in Figure 21. Thus, while in Figure 3 the center of the bottom 21 is depressed to form a deeply depressed surface (corresponding to the center portion 1 of Figure 1) in a section along line B-B, the center of the bottom surface 21 of the mold is, in contrast, protruded (corresponding to the center portion 4). Partitions 22 are provided face-to-face at both sides of the bottom, and each tip portion of the partition 22 is bent to form hook-shaped portion 23. The hook-shaped portions face each other and are bent inward. The fastener body 12 as mentioned above is set and clamped under the hook-shaped portions 23 in a state as shown by a dotted line in Figure 3. After setting the fastener body 12 in the mold in such a manner, a liquefied foamable composition of urethane is injected in the mold. Then, an upper portion 24 of the mold is put on the lower portion 20, and the composition is foamed in the mold. Thereafter, the fastener body 12 is pressurized onto the bottom surface 21 of the lower portion 20 of the mold by interior pressure, as indicated by the solid lines in Figure 3, and the fastener body 12 is integrated with a foamed urethane (the cushioning material 11) along the predetermined three-dimensional curved surface of the bottom 21 of the mold. After the composition is hardened, the cushion body 10 is removed from the mold by opening the upper portion 24 of the mold. Slab-urethane 14 positioned on the end portion of the fastener body 12 is soft so that the fastener body 12 clamped in the partitions 22 can be easily taken out therefrom, by-passing the hook-shaped portions 23. As a preferred embodiment, a seat having a three-dimensional curved surface corresponding to a figure of a person who sits thereon as shown in Figures 1 and, has the fastener body 12, which consists of the fastener material 13 (of a surface fastener of KURARE) and foamed urethane foam 14 (a slab-urethane layer) as a supporting material having a selected thickness of 5-15mm and a density of 0.018g/cm 3 -0.040g/cm 3 . The suitable thickness and density depend on a feeling to sit and a required curved surface shape. In practice, for a seat shape having 10mm in depth of a curved depressed surface, the fastener body 12 is made of a supporting material of a urethane foam having a thickness of 10mm and a density of 0.034g/cm 3 . Also, it is found that a feeling to sit can be better by forming a gap 17 by opening the periphery of the fastener body 10 in a range of 5-20mm from the side portion of the cushioning material 11, dependent on the dimension of the bucket of the seat. As described above, in accordance with the present invention, a fastener body consisting of a fastener material connected with a supporting material layer, which is basically the same material as a cushioning material, is fitted with an interior geometry of a mold for shaping the cushioning material and the fastener body, and a cushion body is formed by integrating the fastener body with the cushioning material along a predetermined three-dimensional curved shape by an internal pressure due to expansion molding of the cushioning material. That is, it is achieved by the present invention to form a fastener material having a predetermined or desired three-dimensional curved surface. This has not been able to be achieved by the prior art. The three-dimensional curved surface is structured by positioning the fastener body into the cushioning material so that a car seat cushion this cushion body can provide good feeling to a person who sits down thereon and can provide comfort to the person, as the cushion body fits withe the figure of the person. The most important factor is that by embodying a cushion body with such a fastener material, the step of attaching a surface material thereon is facilitated, it avoids providing production equipment as used in the prior art, it enables rapid response to variation of production, and high-quality car seats can be supplied rapidly without a substantial cost increase.

Claims: A car seat cushion (10) comprising a cushioning material (11) having a seating surface, a fastener body (12) having an undersurface affixed to said seating surface and an upper surface having a plurality of fasteners disposed thereon, and a surface material (15) covering said cushioning material and attached to said fasteners, the cushioning material being formed by injection moulding to have a center portion (1) and rising side portions (2, 3) to either side of said center portion (1), said center portion (1) having a three-dimensional curved surface, characterised in that said fastener body (12) is inserted as a planar body in the portion of the mould corresponding to the center portion and moulded with the cushion material whereby the injection moulding pressure causes the fastener body to have an upper surface duplicating the three-dimensional curved surface of said center portion (1) whereby the surface material (15) assumes the three-dimensional curved shape of the seating surface. A car seat cushion as claimed in claim 1, wherein said surface material (15) is sutured at the juncture between the cushioning material (11) and the fastener body (12). A car seat cushion as claimed in claim 2 in which a gap is formed between the rising portions of the seating surface and the fastener body (12) in which gap the suture is positioned. A car seat cushion as claimed in claim 1, 2 or 3 in which said fastener body (12) comprises a urethane foam slab (14) and a fastener material (13) fixed thereon. A car seat cushion as claimed in claim 4, in which said urethane foam slab (14) and said fastener body (13) are fixed to each other by lamination. A car seat cushion as claimed in claim 1, 2 or 3 in which the fastener body includes a foam slab layer affixed to the centre portion of the seating surface and a fastener material on said upper surface carrying said plurality of fasteners A car seat cushion as claimed in any preceding claim in which the fastener body comprises the same foam material as the cushion material

Inventors: KINOSHITA YUKIHIRO, MATSUOKA CHIKARA, WAKIMOTO KUNIHISA, WATADANI TAKESHI, KINOSHITA, YUKIHIRO, MATSUOKA, CHIKARA, WAKIMOTO, KUNIHISA, WATADANI, TAKESHI, KINOSHITA, YUKIHIRO NAMBA PRESS WORKS CO., LTD., MATSUOKA, CHIKARA NAMBA PRESS WORKS CO., LTD., WAKIMOTO, KUNIHISA NAMBA PRESS WORKS CO., LTD., WATADANI, TAKESHI NAMBA PRESS WORKS CO., LTD.
Applicants: NAMBA PRESS KOGYO KK, NAMBA PRESS WORKS CO., LTD.
Application year: 1994
Main classification: B68G7
IPC codes: B29C44, A47C7, B29K105, B60N2, B29C39, B29L31, B68G7